Fluid control valve is disclosed in Japanese Patent Unexamined Publication No. 56-94079, a fuel injection valve for an automobile disclosed in U.S. Pat. No. 4,360,161 or the like, and an idling air amount control valve for an automobile in disclosed in Japanese Patent Unexamined Publication No. 64-24133 with each being designed in such a manner that a rod-like valve shaft provided with a valve body is axially moved by driving means, e.g., an electromagnetic solenoid, so as to open/close the valve to thereby control a flow rate of a fluid.
In these conventional examples, no consideration is given to the fact that slight gaps between the valve shaft and bearing means induce vibration and inclination of the valve shaft in a direction perpendicular to the shaft. Consequently a number of problems arise namely, the flow rate characteristics of the fluid cannot be reproduced and reliability of the valve operation will not be satisfactorily obtained. Furthermore, the valve shaft is imbolized when the gaps between the valve shaft and the bearings are clogged by particles generated as a result of wear of the valve shaft; additional wear particles adhere to or accumulate on a valve seat or the surface of the valve body so as to interfere with complete closing of a valve opening.